Sudden cardiac arrest (SCA) is one of the most critical medical problems in the world today. In the United States alone, SCA results in the death of over 325,000 people each year. Most sudden cardiac deaths are caused by ventricular arrhythmias like ventricular tachycardia (VT) and ventricular fibrillation (VF).
Angina pectoris, i.e., chest pain commonly referred to as angina, may occur during ischemia such as acute myocardial infarction, i.e., a heart attack, which is generally caused by occlusion of a coronary artery. Angina can also occur for other reasons including coronary vasospasm, a condition when coronary blood vessels spasm, leading to vasoconstriction. Coronary vasospasm is not necessarily life-threatening, but may be in some instances as coronary vasospasm can result in ischemia and even myocardial infarction. Coronary vasospasm may occur adjacent to a fixed stenosis, which can increase the likelihood of ischemia.